Scalability

Horizontal scaling is achieved in the OpenSSO Enterprise environment
by connecting multiple host servers so they work as one unit. A load-balanced
service is considered horizontally scaled because it increases the
speed and availability of the service. Vertical scaling, on the other
hand, is increasing the capacity of existing hardware by adding resources
within a single host server. The types of resources that can be scaled
include CPUs, memory, and storage. Horizontal scaling and vertical
scaling are not mutually exclusive; they can work together for a deployment
solution. Typically, servers in an environment are not installed at
full capacity, so vertical scaling is used to improve performance.
When a server approaches full capacity, horizontal scaling can be
used to distribute the load among other servers.